150 BALSAMINACEAE 



Sack one-half as broad as long or less, gradually tapering into the spur; flowers 

 unspotted. 

 Sack about 2 cm. long; flowers light yellow. 3. /. occidentalis.. 



Sack about 12 mm. long; flowers golden-yellow. 4. /. aurella. 



Spur wanting. 5. /. ecalcarata. 



Family 70. LIMNANTHACEAE. Fal.se Mermaid Family. 

 1. FLOERKEA Willd. False Mermaid. l. F. occiclentalis. 



Family 71. ZYGOPHYLLACEAE. Caltrop Family. 



Leaves digitately 1-7-foliolate; stipules spiny; stamens with scale-like appendages. 



1. Fagonia. 

 Leaves abruptly pinnate; stipules in ours not spiny. 



Shrubs with endosperm; fruit woolly; stamens with scale-Uke appendages. 



2. COVILLEA. 



Herbs without endosperm; corolla mostly yellow; stamens without scale-like appen- 

 dages. 



Fruit dividing into 5 (by abortion sometimes fewer) carpels, each with 3-5 one- 

 seeded compartments, spiny. 3. Tribulus. 



Fruit dividing into 8-12 (twice as manj as the original carpels) one-seeded nutlets, 

 merely tubercled. 4. Kallstroemia. 



1. FAGONIA L. 1. F. californica. 



2. COVILLEA Vail. Creosote Bush, Hediondilla. i. c. glutinosa. 



3. TRIBULUS L. Bur-nut. l. T. terrestris. 



4. KALLSTROEMIA Scop. Caltrop. 



Plant sparingly pubescent or glabrate; petals 3-5 mm. long; beak much shorter than the 

 body of the fruit. 1. K. brachystylis. 



Plant densely hirsute; petals 5-6 mm. long; beak slightly shorter than the bodj'. 



2. K. hirsutissima. 



Family 72. RUTACEAE. Rue Family. 



Frmt a samara; cells of ovary 2-ovuled; trees or shrubs with digitately compovmd leaves. 



1. Ptelea. 

 Fruit a capsule; cells of ovary 5- or 6-ovuled; undershrubs or low shrubs with simple 

 leaves. 2. Thamnosma. 



1. PTELEA L. Hop-tree, Shrubby Trefoil. l. P. Baldwinii. 



2, THAMNOSMA Torr. & Frem. 



Shrubby; coiolla S-10 mm. long; capsule distinctly stipitate. 1. T. montana. 



Herbaceous from a woodv base; corolla about 4 mm. long; capsule sessile or subsessile. 



2. T. texana. 



Family 73. POLYGALACEAE. Milkwort Family. 



1. POLYGALA (Tourn.) L. Milkwort. 



Plants herbaceous, unarmed; keel with a fimbriate crest. 



Annuals; leaves verticillate, narrowly linear. 1. P. terticillata. 



Perennials; leaves alternate. 



Leaves linear or linear-oblanceolate. 2. P. alba. 



Leaves lanceolate to ovate. 3. P. Senega. 



More or less spiny undershrubs; keel not crested, but with a beak. 



Plant 5-15 cm. liigh; flowers 7-10 mm. long. 4. P. subspinosa. 



Plant 3-10 dm. high; flowers 3-4 mm. long. 5. P. acanthoclada. 



Family 74. EUPHORBIACEAE. Spurge Family. 



Flowers not in involucres; calyx of several sepals. 



Corolla present in either the staminate or pistillate flowers, or in both. 



Stamens 5 or 6; filaments distinct. 1. Croto.V. 



Stamens 10; filaments monadelphous. 2. Ditaxis. 



Corolla wanting. 3. Tkagl\. 



Flowers In involucres; calyx represented by a minute scale on the fllament-Uke pedicels. 

 Glands of the Involucres with petal-hke appendages, these however sometimes much 

 reduced. 

 Leaves all opposite. 



Leaf-blades obUque at the base. Inequilateral; glands 4. 4. Ch.am.\esyce. 

 Leaf-blades eqtiilateral, not oblique at the base; glands 5. 



5. Zygophyllidium. 



